Chromium oxide catalysts are a type of industrial catalyst that is commonly utilized in heterogeneous catalytic processes. Their outstanding catalytic activity is accomplished through the efficient interception of unsaturated coordination and favored surface aggregation. However, the increase of surficial unsaturated coordination and its structural characterization continues to challenge the limitations of chemical synthesis and atomic decoding of nanocatalysts. In this study, a thermal shock method was employed to intercept a significant number of unsaturated coordination and high-valence chromium species in CrO_x-based nanocatalysts. The transformation of nearest-neighbor symmetry from octahedral to tetrahedral was discovered to be centered on the surface of the nanoparticle through the atomic recognition of chromium species using the pair distribution function (PDF) and reverse Monte Carlo (RMC). The catalytic efficacy of symbolic catalytic reactions, such as the dehydrogenation of propane, toluene oxidation, and benzyl alcohol oxidation, is enhanced by the precise synthesis of the surficial active sites. Our results demonstrate a convenient chemical synthesis method that preserves the metastable structure of oxide catalysts under thermal shock. The atomic structural understanding also offers an intuitional experimental model for the study of reaction mechanisms.

中文翻译：

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丰富高性能氧化铬催化剂的不饱和配位


氧化铬催化剂是一种工业催化剂，常用于非均相催化过程。它们出色的催化活性是通过有效拦截不饱和配位和有利的表面聚集来实现的。然而，表面不饱和配位的增加及其结构表征继续挑战纳米催化剂的化学合成和原子解码的局限性。在本研究中，采用热冲击方法拦截了 CrO_x 基纳米催化剂中的大量不饱和配位和高价铬物种。通过使用对分布函数 （PDF） 和反向蒙特卡洛 （RMC） 对铬种类的原子识别，发现最近邻对称性从八面体到四面体的转变以纳米颗粒表面为中心。象征性催化反应的催化作用，如丙烷脱氢、甲苯氧化和苯甲醇氧化，通过表面活性位点的精确合成而得到增强。我们的结果表明，一种方便的化学合成方法在热冲击下保留了氧化物催化剂的亚稳结构。原子结构理解还为研究反应机理提供了一个直觉实验模型。